8-chloroimidazo[1,2-a]pyrazine (5.2 g, 33.9 mmol) and N-iodo-succinimide (NIS) (8 g, 35.6 mmol) were combined with DMF (34 ml). The reaction mixture was stirred at RT for 48 h. After that, the water was added to the suspension, and the solid was filtered, washed with water and MeOH, and dried under HV to afford 8-Chloro-3-iodoimidazo[1,2-a]pyrazine (7.17 g, 25.6 mmol, 75.8% yield).